1. Field of the Invention
The present invention relates generally to a method and apparatus for routing between mobile networks, and in particular, to a method and apparatus for routing between mobile networks without the aid of a home agent (HA) by acquiring the internal network prefix of a neighbor mobile network.
2. Description of the Related Art
FIG. 1 is a diagram illustrating an exemplary mobile network configuration. The mobile network is built with one or more mobile routers (MRs) and other mobile network nodes (MNNs). The MNNs communicate with an external network via the MRs. The MRs are connected to a backbone network through an access router (AR), thereby enabling mobile network communications. The AR is accessible by a plurality of MRs and thus, an access network that the AR takes charge of may include a plurality of mobile networks. The backbone network is provided with an HA for supporting seamless communications for mobile networks regardless of movement. In other words, the MRs communicate with the HA through tunnels established between them. Another mobile network may exist within a mobile network by use of an MR.
Referring to FIG. 1, mobile networks access the AR via MR1 and MR2. MNN1 and MNN2 are connected to MR1 and MNN3 is connected to MR2. MR3 with MNN4 is connected to MR2. The backbone network has an HA taking charge of communications for MR1, HA_MR1 and an HA taking charge of communications for MF1, HA_MR2, and an HA taking charge of communications for MR3, HA_MR3.
If MNN1 wants to communicate with MNN3, MR1 transmits data packets to HA_MR1 through a tunnel via the AR. HA_MR1 then transmits the data packets to HA_MR2 according to data packet destination information, and HA_MR2 transmits the data packets to MR3 through a tunnel established between MR2 and HA_MR2 via the AR.
In this case, since the mobile network of MR1 is close to that of MR2, it is preferred that MR1 and MR2 communicate with each other directly without the aid of the HAs associated with MR1 and MR2. However, MR1 has no knowledge of the existence of MR2 the internal network prefix of MR2 under conventional technology. As a result, communications are conducted via HAs associated with MRs.